Leakage finding and plugging method for well leakage of long open hole section

Abstract

The invention relates to a leakage finding and plugging method for well leakage of a long open hole section. The leakage finding and plugging method sequentially comprises the following steps: (1) the long open hole section is divided into a plurality of small sections, and sufficient plugging slurry with required concentration is prepared according to the size of a well hole, the length of the open hole section and the leakage speed; (2) a drilling tool is descended to the well bottom, and an initial leakage speed S0 and a pressure bearing value P0 of the well section are recorded; (3) the volume of the leaking stoppage slurry required by a first well section at the lowermost part of the divided well sections is calculated; (4) according to the calculated amount, leaking stoppage slurry is injected, the liquid level of the leaking stoppage slurry reaches the upper portion of the first well section, after injection is completed, the drilling tool is lifted to the safe well section, solidification waiting is conducted for 12 hours, and the leakage speed S1 and the pressure bearing value P1 at the moment are recorded; and (5) if the leakage speed S1 is less than the leakage speed S0 by more than 20%, or the pressure bearing value P1 is greater than the pressure bearing value P0 by more than 20%, the first well section has a main leakage point, the first well section continues to be plugged until the whole well section does not leak any more or the pressure bearing value P1 is increased to a preset value, and plugging is finished. According to the method, on-site existing resources can be utilized, and the leakage horizon can be simply, practically and rapidly determined.

Description

technical field [0001] The invention relates to a leak detection and plugging method for petroleum drilling, in particular to a leak detection and plugging method for long open-hole section well leakage, and belongs to the technical field of petroleum drilling. Background technique [0002] Drilling fluid loss is a common downhole complex situation in drilling operations. Once a loss occurs, it will not only delay drilling time, lose drilling fluid, damage oil and gas layers, interfere with geological logging work, but may also cause well wall instability and lead to well collapse A series of complex situations and accidents, such as drill sticking, blowout, etc., even lead to the scrapping of the wellbore, resulting in significant economic losses. For example: Well Ebaye 1, which was implemented in recent years, encountered karst vug leakage, the whole well lost 27,850 m³ of drilling fluid, consumed 1,484 tons of plugging materials, lost 61.2 days of time, and had an econom...

AI Technical Summary

Problems solved by technology

In the actual application of these methods, due to the influence of various factors, there will be a large deviation between the predicted leakage layer and the actual one. Due to the application of software, equipment and instruments, the construction cost is high and the cycle is long, resulting in a substantial increase in operating costs.

Although the empirical method is more practical in the field, when there are multiple leak points, it is difficult to judge which leak layer is leaking

When multiple lost zones are encountered during the drilling of long open hole sections, if the main lost location cannot be determined, it is necessary to repeatedly try and search for lost circulation, which not only consumes a lot of plugging materials, but also wastes a lot of time

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